1. Field of the Invention
This invention relates generally to lift cords used with window shade assemblies, and, more particularly, the invention relates to safety devices used with such window shade lift cords.
2. Description of the Prior Art
Window shade assemblies and venetian blinds typically have window covering material or blind slats extending between a headrail and bottomrail and two or more lift cords connected to the bottom. Within the headrail is some type of cord locking device. Typically, two or more lift cords are connected at one end to the bottomrail and extend up through the window covering material or blind slats into the headrail. The lift cords then pass through a cord locking device and out of the headrail such that an opposite end of the lift cords is accessible to an operator. Two lift cords may be formed from a signal length of cording. This general arrangement can be seen in prior art FIG. 1.
This type of window shades and blinds are typically raised by the operator pulling on the accessible portion of the lift cords and are lowered by releasing the lift cords. Because all lift cords must move in unison, the lift cords are typically tied together or otherwise looped as can be seen in FIG. 1. The lift cords often extend downward from the headrail to within a few feet of floor level.
The lift cords of the window shade assembly present an attractive danger to infants or children who may play with the lift cords. There have been several instances in which children and infants have become entangled in the cords and accidentally hanged.
In the past, attempts to reduce the danger associated with these lift cords have focused on moving the lift cords out of the accessible range of infants such as by tying or clipping the cords to shorten them or otherwise moving the lift cords away from floor level and away from the infants reach. Moving the cords out of the way after use is troublesome, and the operator must remember to move the cords after each use. Other attempts have focused on a detachable connection of the lift cords ends such as is disclosed in U.S. Pat. No. 4,909,298 to Langhart et al. Detachable lift cords require a certain level of force to detach. Moreover, recent tests of the commercially available embodiment of the Langhart patent have shown that this product failed to detach in simulated entanglements. And although window shade assemblies are designed to be aesthetically pleasing, none of the attempts of the prior art to reduce the dangers associated with lift cords are particularly aesthetically pleasing. Thus, there is a need in the industry to reduce the danger associated with lift cords which does not require any separate actions by the operator, in an efficient yet aesthetically pleasing manner.